From: Dave Martin <Dave.Martin@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Suzuki Poulose <suzuki.poulose@arm.com>
Subject: [PATCH] arm64: cpufeature: Fix missing ZFR0 in __read_sysreg_by_encoding()
Date: Mon, 3 Jun 2019 16:35:02 +0100 [thread overview]
Message-ID: <1559576102-12156-1-git-send-email-Dave.Martin@arm.com> (raw)
In commit 06a916feca2b ("arm64: Expose SVE2 features for
userspace"), new hwcaps are added that are detected via fields in
the SVE-specific ID register ID_AA64ZFR0_EL1.
In order to check compatibility of secondary cpus with the hwcaps
established at boot, the cpufeatures code uses
__read_sysreg_by_encoding() to read this ID register based on the
sys_reg field of the arm64_elf_hwcaps[] table.
This leads to a kernel splat if an hwcap uses an ID register that
__read_sysreg_by_encoding() doesn't explicitly handle, as now
happens when exercising cpu hotplug on an SVE2-capable platform.
So fix it by adding the required case in there.
Fixes: 06a916feca2b ("arm64: Expose SVE2 features for userspace")
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
---
There is a broader question about how to avoid this happening again, but
I couldn't see an obvious solution so far.
---
arch/arm64/kernel/cpufeature.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index ca27e08..80babf4 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -830,6 +830,7 @@ static u64 __read_sysreg_by_encoding(u32 sys_id)
read_sysreg_case(SYS_ID_AA64PFR0_EL1);
read_sysreg_case(SYS_ID_AA64PFR1_EL1);
+ read_sysreg_case(SYS_ID_AA64ZFR0_EL1);
read_sysreg_case(SYS_ID_AA64DFR0_EL1);
read_sysreg_case(SYS_ID_AA64DFR1_EL1);
read_sysreg_case(SYS_ID_AA64MMFR0_EL1);
--
2.1.4
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
reply other threads:[~2019-06-03 15:35 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1559576102-12156-1-git-send-email-Dave.Martin@arm.com \
--to=dave.martin@arm.com \
--cc=catalin.marinas@arm.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=suzuki.poulose@arm.com \
--cc=will.deacon@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).